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In the past I have just created a small batchfile program to repetitively copy text files to fill up a disk and overwrite any data that had been previously erased. The idea is to make sure you really write something into most if not all of each sector so you really get just about everything.

I was just wondering if anyone had some real facts on using a method like this as opposed to purchasing something more fancy? Anyone ever try to recover data from a disk that has been written over? I used to do data recovery of disks that were NOT overwritten and that was hard enough...!

I am approaching this from the view that once you overwrite the data once, it's beyond the reach of anyone not looking for government secrets. That is, the amount of effort it would take to recover anything useful would not be worth the trouble.

I use DBAN boot and nuke dban.sourceforge.net
to wipe any hard disks, and it has the advantage of no cost and open source, so I've figured it was better then the file overwrite process, and it didn't involve buying anything.

If you are trying to overwirte areas with out wiping out the entire dirve, there is other software. If you use the text file method you need to check out the end of the file with a raw hex editor that can look past the EOF character in the file. I've seen data in sectors past the end of the EOF mark that was the origional data on the disk.

It's like the OS read the sector from the disk and only put data to the EOF mark and didn't clear out the rest of the buffer with 00 so the same data was written back to the disk in the slack space between the last character in the file and the end of the allocation block for the file. (now I'm not positivebthis was Windows, Dos, MCP, CPM, AppleII DOS, CTOS or some other operating system.)

For overall drive wiping, I will second the nomination for DBAN -- great stuff.

For less-than-total annihilation, I've had good luck with a program called Eraser. This runs in Windows, and can do either on-demand or scheduled wiping; it will let you choose specific files/folders (via GUI or context menu) and also has a "wipe free space" option for clearing out junk on a drive. Very cool, simple interface, and free:

I'm no data-recovery expert, but from what I have learned, I'd agree with your assessment that in most cases, it takes a very determined (or very smart) individual to recover data -- even if it hasn't been overwritten.

Being a paranoiac about my privacy, however, I have used the Gutman method the few times I've actually wiped a drive.

To address the question of particular software, I'd have to agree -- personally speaking -- that DBAN is also my favorite. However, I wanted the article to offer an unbiased, objective look at the available products on the market (I hope I have done this) without interjecting my own feelings into it. Everyone has their own opinion, and it would be unfair for me to write a fact-based article according to my own preferences.